Regarding the person Laura Poitras we hear mention of in regards Glenn Greenwald

[Babel_17]

54. I think it was intended for Greenwald who lives in Brazil

Miranda was searched during a stopover, he wasn't in Britain so as to visit the Guardian.

So, you could say he was a Brazilian citizen who was traveling from Germany to Brazil who was interrogated and had his belongings taken away from him because his flight passed through Britain.

And this happened due to the powers granted by an anti-terrorism law.

In August 2013, while travelling home from a visit to Germany, carrying work in progress relating to classified U.S. government documents to Greenwald in Brazil,[62] Miranda, 28, was detained by the Metropolitan Police Service at London's Heathrow Airport under Schedule 7 of the Terrorism Act 2000.[63][64] Miranda was detained for nine hours, the maximum time permissible under Schedule 7.[64] Miranda was returning from Berlin, where he had been assisting Laura Poitras, Greenwald's collaborator on the Snowden files.[64] His flights were paid for by The Guardian, for whom Miranda does not work, although he sometimes assists Greenwald on stories. Greenwald described his partner's detention as "clearly intended to send a message of intimidation to those of us who have been reporting on the NSA and GCHQ".[64]

https://en.wikipedia.org/wiki/Glenn_Greenwald#Personal_life

Edit: spelling